| As one of the main vulnerable part,the service life and service performance of the sliding bearing at the shovel arm joint of the excavator is directly affect the working reliability of the excavator.It has great significance to improve the overall performance of the excavator by carrying out research on the life evaluation and service performance of the sliding bearing.In this paper,a new type of excavator shovel arm bearing test machine is developed,and the service performance and life evaluation of the test bearing can be evaluated on line,and also the corresponding conditions for the optimal friction and wear performance of excavator shovel arm bearing are established.The main research contents are as follows:The overall design of the excavator’s shovel arm bearing test machine: according to the life test principles and technical requirements to determine the overall scheme of the sliding bearing test machine.According to the function requirements of each subsystem,the scheme design and mechanical structure design of each subsystem are completed,including the design of the swing system,the design of the loading system,the design of the fixture system,the design of the inspection system,the design of the lubrication system and the selection of some components,and also complete the overall design of the excavator’s shovel arm bearing test machine.The dynamic and static analysis of the key parts of the test machine: the struction static analysis and the dynamic analysis of the key parts of the test machine were carried out by using ANSYS Workbench software,which to verify whether the strength and stiffness of each part meet the design requirements.In addition,the pre-stressed modal analysis of the test machine frame was carried out,and the vibration mode and the natural frequency of the frame were obtained,and the vibration characteristics of the frame were determined.Optimization design of multi target response surface of the test machine frame: the multiple target response surface optimization method is used to optimize the structure of the test machine frame.Taking the full load condition as the research condition,the thickness of the frame as the design variable,the overall mass of the frame as the objective function,the maximum stress,the maximum total displacement and the first order natural frequency as the state variables to optimize the structure of the test machine frame.Performance verification of the test machine and test evaluation of the bearing service life: the online test for the loading force,the wearing volume,the swing angle and the temperature of the test machine is carried out,and the performance test of the test machine was also completed,which verifies the performance requirements and the functional requirements of the test machine.At the same time,the service performance and life evaluation of the test bearing under different conditions of oil groove,grease and grease injection are completed on the test machine,and the friction and wear performance of the excavator shovel arm bearing was studied.The research work of this paper provides the theoretical guidance for the design and development of the new type of sliding bearing performance evaluation test equipments. |
